“To all those who have died and were injured in the heartless attacks in Paris, and to all the people in France: Nos plus sincères condoléances,” the pair wrote.

Prince William watched Kate Middleton write in the book of condolences at the French Ambassador's residence in London on November 17, 2015 following the attacks in ParisNiklas Halle'n/AFP/Getty Images

The Duke and Duchess of Cambridge, both 33, have been traveling throughout the country these past few weeks, and recently visited Dundee, Scotland, to take part in the Scottish Mental Health Arts and Film Festival.

“In many ways I feel torn, because it’s like, why am I up here dancing and having fun when people are crying over the loss of their loved ones?” Madonna said during an emotional speech at her Stockholm show on Saturday, Nov. 14. “However, that is exactly what these people want to do. They want to shut us up. They want to silence us, and we won’t let them. We will never let them.”